Sequential motor operation



2 Sheets-Sheet l Feb. 20, 1951 J. T. GATES ET AL SEQUENTIAL MOTOR OPERATION Filed 00?.. 4, 1949 Feb. 20, 1951 J. T. GATES ET AL SEQUENTIAL MOTOR OPERATION 2 Sheets-Sheet 2 Filed Ost. 4, 1949 Y @im 5 if?. N rr R NAM/M o t6/ r W556i /w d Patented Feb. 20, 1951 l- UNITED STATES PATENT OFFICE SEQUENTIAL MOTOR OPERATION James T. Gates and George H. Lister, Cleveland, Ohio, and Albert R. Panetta, Malden, Mass., assignors, by mesne assignments, to Machine Circuit Control Co., Cleveland, Ohio 4- The invention disclosed herein relates to the Control of sequential motor operation of two motor sets that are designed to be started and run for a period of time with the performance of associated mechanisms. As an example of such an installation, the invention is adapted to the successive operation of movie projector machines that involve the timed operation of shutters, dousers, sound transposing means, and light sources, etc., incident to the reproduction of pictures and sound from traveling strips driven by either one Vof the projector machines somewhat as'accomplished by the invention claimed in a copending application filed by James T, Gates on May 27, 1948, as Ser. No. 29,472. At the concluding run of either machine, devices are set into operation that start the operation of the companion machine, the switchover being instituted by a specific frequency signal incorporated in the sound track of the traveling strip, in conjunction with means and mechanism that responds to the specific frequency for starting and running of a cycling motor and switches that effects the timed operation of the projector motor and its associated devices. and mechanism for initiating the operation of the cycling motor includes electronic circuits that control the level of the signal effected by the specilic frequency and pass it through a low pass filter to exclude all frequencies above 45 cycles, which are amplified and limited in the nature of a sorting device that feeds a frequency selecting network. lsolating the filter network from the following relay tubes and permitting the 45 cycle signal to be amplified for first relay operation, which conjoins with a time ldelay means to fire the terminating tube initiates start of a switching motor. The switching motor drives cams for operating switches, which in conjunction with conditioning andselector switches control the successive operation of the two motor devices.

Embodiment of the invention according to the foregoing accomplishes the object to pick out a particular frequency from a mixture of sound signals, and use it for selective operation of a control circuit after filtering, limiting and amplifying, rejecting all but the selected signal frequency, and isolating and further amplifying for relay operation. The electronic initiating network therefore discriminates the actuating impulse, selected as a 45 cycle per second frequency because of its relatively infrequent occurrence of instrument tone differences or overtones.

Further objects and advantages of the present invention-will -be apparent from the following de- The frequency responding means Application October 4, 1949, Serial No. 119,472 5 Claims. (Cl. S18-102) scription, reference being had to the accompanying drawings wherein a preferred embodiment of the present invention is clearly shown.

In the drawings:

Fig. 1 is a circuit diagram of an initiator circuit adapted to pick off a specific frequency and translate it for the initial energization of a motor control circuit, a part of which is also shown schematically.

Fig. 2 is a circuit diagram of a motor control circuit adapted to effect the sequential operation of duplicate sets of interconnected devices whose timed operation is critical to the successful performance of the apparatus, a portion of this iigure being a repetition of part of the circuit shown in Fig. 1.

Referring specifically to the drawings, reference characters I to 8 inclusive refer to separable connections, such as plug and jacks, between the initiator and the circuit controller, powered by a D. C. source of electric current controlled by a master switch 9. Pick-up means Illa and ib respond to a frequency signal produced by the combination of a light beam from the lamp lla or Hb and a frequency trace 12a or l2b on a film or other medium i3d or |31) either one to feed an amplifier I4 for audible rendition over the output lines E6 and Il by a speaker I5. The amplifier gets its power from a suitable source by the lines I8 and I9, while lines 2t and 2| tapping into the amplifier output I6 and Il connect with plug receptacles l and 2 and thereby impress the output of the amplifier lll upon a potentiometer Rl.

By the potentiometer Rl the operating level of the initiating device is adjusted for any given setting of the theater amplifier. The potentiometer RI is adjusted to the particular amplifier used so that the set level of the unit will give operation to a 45 cycle signal and non-operation for all other frequencies. A resistor R2 and capacitor Cl form a low pass filter that serves as a preliminary filter by preventing frequencies above 45 cycles from passing on to the first tube TI, through the coupling capacitor C2. The tube TI acts as a limiter and amplifier, since it amplilies all signals received, but only up to a given level, so that there is obtained a gain in the ampliication of smaller signals over the amplification of signals of greater intensity. The action of tube TI is to be thought of as a preliminary sorting device for segregating the 45 cycle signal. In its service as an amplifier, tube TI increases the utility of the device in that it allows operation from a low level output.

The signals from the output of the limiteramplier Ti are fed through the coupling ca pacitor C5 into a selector comprising the network N and the tube T2, which selector is a degenerative or very low gain amplifier for all but the 45 cycle signals. The network N consists of resistors R6, R1, R8 and R9 along with capacitors C6, C1, C8 and C9, and operating in conjunction with tube T2 forms a frequency sensitive or 45 cycle pass iilter, It is tuned to amplify the 45 cycle signal and reject all others. Capacitors C8 and C9 could be combined into a single unit.

The output of the selector is capacitatively coupled by C1 1 to tube T3, a buffer amplifier serv ing to isolate the high impedance frequency circuit from the low impedance grid circuit being coupled as a cathode follower to a thyratron tube T4 through the resistance-capacitor coupling C13, R16. The buffer-amplifier output controls the first gas discharge tube T4 through the capacitive coupling C13. Tube T4 is of the thyratron type and under control of tube T3, its firing simultaneously discharges approximately 80 volts D. C. to the relay L1 that has a normally closed contact a and an open contact b with a cooperating armature connected through resistor R18 as the input to the signal grid of a second thyratron T5. When the' first gas tube T4 is nonconductive, the relay L1 is closed against contact a, and condenser C16 has a full negative charge about ?8 v.) applied to it which it obtains from the rectifier and lter D2, C20. C16 chares almost instantly whenever relay L1 is unenergized closin contact a. When built up to a limited voltage the capacitor C16 upon connection to ground through R21, discharges to fire the second thyratron T5. The two seconds required for discharge of the capacitor C16, forestalls ring the second thyratron T5 by overtones or high intensity beats that frequently occur in music, and which may be enough to effect the firing of tube T4. When the relay L1 is energized the normally open contact b is engaged which discharges the capacitor C16 to ground through resistor R21. In two seconds tube T5 will fire and relay L2 will be energized.

Tube T4 is the tube that operates relay LI whenever the frequency of the input signal is 45 cycles. When tube T4 conducts and relay L1 closes against contact b, capacitor C16 which is tied to the grid of tube T5 through resistor R18, is removed from the point of negative voltage and grounded through resistor R21, which permits capacitor C16 to discharge at a rate proportional to CR until the grid bias is reduced sufficiently to allow tube T5 to conduct. Tube T5 fires whenever its grid is connected to ground, and operates the control relay L2 that starts or initiates the operation of the changeover device. The firing of tube T5 may bemanually controlled by closing a push button switch S1,

The initiator is powered from a D. C. source, when the switch 9 is closed, by a transformer 22 Whose primary 23 induces high potential current in secondary 24 and low potential current in secondary 25 suitable for supply to thevarious circuit elements of the controller. Current from 24 is rectified by D1 and ltered by resistors R20, R21 and capacitors C18, C19 to provide plate current for tube T1 by conductor 26 and resistor R5, for tube T2 by branch 21 and resistor R12, and for tube T3 by 21 extended. Unrectified plate supply is provided by lead 28 through the winding of relay LI and load resistor R11 to the plate of vtube T4, and a branch 29 leads to the winding of relay L2 and by way of resistor R19 to the plate of tube T5. Current from 25 is rectified by D2 and filtered by c-apacitor C26 and resistors R25 and R26. The secondary 25 provides low voltage current for the iilaments or heaters of the tubes T1 to T5 inclusive, somewhat as indicated by lead 30 to tube T1. Grid bias and cathode potentials are provided for all of the tubes in the conventional manner as shown, and includes the lead 31 connecting to the grid of tube T4 through the resistor R16, as well as a lead 32 connecting to contact point a of relay L1. The signal grid of tube T5 is directly connected with one of the contacts of the manual switch S1 by lead 33, and to one of the contacts a of the relay L2 by lead 34, which has an extension 35 connecting with receptacle 1. The other contact a of L2 connects by lead 36 to receptacle 6. A second set of contacts b on the rel-ay L2 are connected by leads 31 and 38 to receptacles 4 and 5. Power lines 39 and 49 furnishing D. C. to the transformer 23, also branch at 41 and 42 respectively to connect with receptacles 3 and 8 respectively and thus com.- plete the connections for the initiator electrically separable from the motor control unit at theV receptacles 3, 4, 5, S, 1 and 8.

The several circuits of the motor control circuit are shown in full on Fig. 2 of the drawings,y and part of which, the upper part of Fig. 2, is also showin at the bottom of Fig. 1. First, as shown in Fig. 1, two D. C. busses are provided, 43 which is connected to the plug of 3 for the negative Side., and 44 that is connected to the plug 8 for the positive side, and across which the various circuit elements are connected by means of switches.v re-v` lays and the like. The principal element of this, device is the cam driving motor 4,5 connected across the positive bus 44 and a lead 46 connected to the plug 5 which in turn connects, by lead 38, the two contacts b of relay L2, and. thence by lead 31, receptacle and plug 4 and line 4,1 to the negative plug and receptacle 3 which leads to the minus bus 39, by 4.1. The line 41 has, a branch 48 leading to one of the contacts a of` switch S2, and lead 46 has a branch 49 connected. to the other Contact a of the switch S2. The switch S2 is operated by the cam 59 when driven. by the motor 45, and cycles to open switch con.- tacts b and close the contacts a followed` by a. return to contacts b for each cycle. One of thev contacts b is, connected to ground at 52, while` the other b contact connects by 53 with` plug 6 the receptacle of which connects by 36 to contact, a Qf L2. as a cycling switch, in. that energizing `0f. the, motor 45 by the firing of tube. T5 and closing of the relay L2, closes a sustaining motor circuit4 through contacts a of switch S2` until the cam, rotates toV the next notch and then opens the, sustaining circuit. In the meantime. other c ir-` cuits are controlled which complete the sequence,` speciiied.

The remaining circuits of the motor control unit may be followed by reference to Fig. 2, where` the devices to be operated in relay fashion or in alternate sequence are the two movie projector motors Ml and M2, each associated with a pilot; lampPI and P2, and an arc lamp A1 and A2 re-. spectively. Each motor and` its associated devices are controlled by switches S3 and S4, actuated by cam 51 when rotated by the motor 45. Thereare other cams all of which are driven by the same motor 45, and include cam 52 that actuate` switches S5 and S6 and cam 53 that actuates-y switches S1 and S8', which switches 55, 56, 51 and 58 control they dousers Z1 and Z2; as welles, cam.

Thus the motor 45 and the cam 5,0 act.

-54 for actuating switches S9 and SIU that control ,opposed relays L5 and L6 for the changeover de- V'vices and locking relays L1 and L8 which in turn control the sound. A greater or lesser number of cams may be driven by the motor 45 for the actuation of additional switches and for control of other devices but the foregoing will suffice to show that several groups of devices may be operated in timed sequence. Speciiic reference to the switches S3 and S4 with their circuits controlled by the gang switches operated by relays L3 and L4 in conjunction with the manually operated `selector switches SI I and SI2 will trace the operation of the control device in starting one of the motors MI and M2 and thence alternately connecting them for operation in repeated sequence.Y

Each of the relay switches L3 and L4 have four pairs of contacts a, b, c, and d adapted to be Ibridged by contactors 56 and 58 under control of .the relay windings connected in parallel by conductor 60 with the negative line 41 to be connected to the current source by bus 4|. The opposite end of the relay windings L3 and L4 is ,connected in each instance by 62 and 64 to a gang contact a whose opposite contact is connected by 66 and G8 to 10 that joins positive bus 44. Each relay winding is also connected by eX- ,tensions I2 and 'I4 to one of the c gang contacts of the other relay, the opposite one of which connects back by 76 and 'i8 to the associated motor control switch, each with a branch 80 and 82 yconnecting to one of the b contacts of selector switches SII and SI2 respectively. The other b contact of each of the selector switches joins by leads 84 and 86 the extensions 'I2 and 'I4 respectively extending between the coils L3 and L4 and the c contacts of the other gang switch. With respect to each set of gang contacts one of the b contacts connects by lead 88 and Se respectively to contact a of switch S3 and to contact b of switch S4. A branch 92 joins 88 and a branch 94 joins 9U to connect to the pilot lamps PI and P2 respectively, both of which are connected to the negativebus 43 by leads 96 and 98 respectively. The other b contact of each pair of gang contacts connects by leads 98 and |08 to motors MI and M2 and have branches |02 and |84 leading to arc-lamp switches AI and A2 respectively, and each of which are joined to the negative bus 43 by connections |06, |88, IIIJ and II2 respectively. The movable element of the switches S3 and S4 are connected to the positive bus 44 by leads II4 and IIS.

A conductor I I8 extends from the plug connection 'I and connects with one of the d contacts of both gang switches, while the opposite d contact connects by I28'and |22 to one of the a contacts of the selector switches SII and SI2 respectively, with a bridge connection |24 joining |20 and |22. The other a contact of each selector switch is joined by leads E28 and I 26 to ground for the 'grid of tube T5, when switches SII or SI2 and L3d or L4d are closed.

Each of the switches S5 to SII) inclusive are single circuit switches operated by the motor driven cams 52 to 54 inclusive, and have their movable contacts connected to the positive bus 44 by leads |39, |32, |34, |35, |38 and |40, respectively. The fixed contact of switches S5 to S8 are connected by |42, |44, |46, and |48 to the douser controls ZI and Z2 which in turn are connected in parallel to the negative bus by line |58. The fixed contacts of the switches S9 and SIU connect by |52 and |54 serially with ,the coils of locking relays L'I and L8 which are 6 joined at |56 to connect with the minus bus 43. Winding of relay L6 and winding y of relay L5 are connected in parallel across |52 and bus 43 while winding y of relay L6 and winding :c or relay L5 are connected in parallel across the bus 43 and connection |54.

The foregoing description of the motor control unit should illustrate that there are two sets of duplicate apparatus, each of which is suscepti ble of being started at the conclusion of a performance by the other. Each set includes a cycling switch S3 or S4,driven by the rnotor 45, a conditioning gang switch L3 or L4, and selecting switches SII or SI2, interconnecting projector motors MI and M2, arc lamps AI or A2, and pilot lamps PI or P2 across the busesv 43 and 44. Other cycling switches S5 to SI8 driven by the cam motor actuate the two douser controls ZI and Z2,.the two changeover relays L5 and L6, and the two locking relays Ll and L8', in proper timed relation.

Whenever the signal grid of the tube T5 is connected to ground, the tube lires, and the relay wincling L2 in its plate circuit is energized to actuate the plunger which closes both pairs of contacts a and b of relay L2. Contacts a of L2 establish a direct but temporary connection between the grid or" T5 and ground through contacts b of switch S2. Contacts b of L2 establish a temporary starting circuit for the cam driving motor 45 over 41, 31, 38 and 48, across the buses 43 and. 44. Rotation of the motor 45 drives the cams 58 to 54, that in turn actuate the switches S2 to Sie to cycle the selected operations. The rst action of the cycling switches in the point of time is the operation of cam 58 to open the contacts b and close the contacts a of switch S2 which opens the ground connection for the grid of tube T5 and establishes a running circuit for the motor 45 through 48, contacts a and 49 bridging the buses 4'! and 44. Thus the ring of tube T5 need be but of short duration. Establishing of any ground connection for the grid of tube T5 causes it to fire. Grounding of the grid by closing of LI and b eiTects a delayed ring of T5 due tothe time constant of CIS and R18, but the grounding of the grid by closing of SI efhcts substantially instantaneous ring of the tube. Any grounding of lead 34 also effects instantaneous firing of the tube.l If contacts a of L2 are closed, the tube T5 will remain conductive so long as switch S2 is closed at the b contacts. The tube will also remain conductive so long as either of the selecting switches SII or SI2 and one of the conditioning switches L3 or L4 remains 'in the rest position bridging the d contacts. The switches SII and SiZ determine which one of the projector motors MI orMZ will be first started and run its cycle during a series Vof operations.

With the parts standing in the relation illustrated and with main switch 9 closed, the motor control circuit would be nonactive except for energization of the pilot light P2 which is connected across the buses through the b contact of switch S4. rlhe circuits for both motors MI and M2 are open at the b contacts of the respective conditioning switch L3 and L4, and the circuit for motor MI is further open at the a. Contact of switch S3. The glowing of pilot light P2 is indicative that motor M2 is operating or would be operating if the conditioning switch L4 were closed at b contacts. Therefore, motor Ml is the motor that normally will startup on the next firing oi the tube 'lube T5 can be made conductive by grounding its grid, either directly through closing of switch Si, through a specific time delay by the electronic actuation of relay switch Li, or through closing of either of the manual selector switches Sli or Sl2. Closing of any one of those switches effects the cyclic operation of cam driving motor 45 which drives all of the cams G to 54 inclusive through half of a rotation, or 180 degrees. With the motor control circuit in the condition shown in Fig. 2, any firing of the tube T5 effects the cycling of motor 45 without energizing any other motor control circuits than the change of pilot lighting. Ifswitch Si is closed, then the motor 45 drives cam 5i through a half turn to shift both switches S3 and St, which energizes pilot iight Pl and deenergizes light P2. The conditioning switches L3 and L4, and the selector switches SH and Si2 being open prevents any other circuits for the motors M! and M2 being completed, and makes it possible to select which one of the sets of motors and mechanisms will be the first to be started in the daily run.

As shown in Fig. 2, closing of either manual switch Sli or Sl2 grounds the grid of tube T5 through the d contacts of either conditioning switch, and renders the tube momentarily conductive. Relay L2 operates to start cam driving motor 45. Closing of switches Sil or Si2 also operates to complete the return circuit for the winding of the associated conditioning switch and thereby selects the motor MI or M2 that will be started first. As an illusiration, closing of Si I completes by its contacts a circuit from b of S3 by 18, Si), 34 and l2 to the coil of L3, and the armature 56 pulling up opens the d contacts and closes the a, b and. c contacts of the conditioning switch Lil. The c contacts establish a holding circuit for the coil of L3, the b contacts complete the circuit for motor Mi except for the open contact a of switch S3, while the c contacts establish` a branch circuit in parallel with the b contacts of the other selector switch Lt. On the other hand, and unser the same conditions of Fig. 2, upon closing of SI2 no circuits would be completed other than the grounding of the grid in tube T5 through the a contacts of SI2 and the d contacts of either Lt or Lil. While the contacts b of S12 would be closed to 'bridge 82 and BES, the line i8 leads to an open contact a at switch S4. In the instance of closing of SII the motor MI would start almost immediately or as soon as the cam 5I rotated far enough to actuate switch S3 and close at Contact ln the instance of closing SI2 the motor M2 would start only after cam 5| had rotated to the alternate position, one half turn from that shown in Fig. 2, or to such position that switch closes against contact a. Except for the feature of selecting which motor MI or M2 starts first, the selector switches SI l and SI2 play no part in the continued operation of the motor control circuit. Both sets of contacts that they control are accounted for by the conditioning switcl'ies L3 and L5. Once the conditioning switches actuated to the circuit closed condition they establish their own holding circuits, and complete the associated motor circuits except for the switches and Sd, which are alternately opened and closed with such designed overlap to effect some simultaneous operation of motors Ml and M2 during the changeover. rllhe selector switches determine which of the pair of apparatus will start rst, and then the initiator attends to the successive operation of both in accordance with the signals on the traveling strip or record.

While the embodiment of the present invention as herein disclosed, constitutes a preferred form, it is to be understood that other forms might be adopted.

What is claimed is as follows:

1. ln a motor control apparatus :for alternately operating each of two motor driven devices in cycles under control of a selected frequency trace actuated by the currently operating motor driven device, initiating means for effecting the start of either motor driven device before the conclusion of operation by a currently operating motor driven device, comprising in combination, means for sorti-ng the selected frequency and limiting the amplification thereof, lter means for passing only the selected frequency after limiting, buffer means for isolating the selected frequency and applying it to following circuits in amplified form, a switching relay circuit controlled by said buifer means and adapted to be energized through degenerative coupling with said buffer, a motor controlling relay circuit including a gas discharge tube for energizing the relay on occurrence of the proper signal evolved from the selected frequency, time delay means connected with the signal grid of said gas discharge tube, and means including said switching relay for connecting said signal grid either lwith a current source or with ground through said time delay means, whereby vequivalent cycles appearing in music as overtones or high intensity beats will not effect firing of the gas discharge tube.

2. In a motor control apparatus for alternately operating each of two motor driven devices in cycles under control of a selected frequency trace actuated by the currently operating motor driven device, initiating means for eifecting the start of either motor driven device before the conclusion of operation by a currently operating motor driven device, comprising in combination, electronic means for discrimination of the selected frequency as an actuating impulse free of associated frequencies, a switching relay circuit controlled by said electronic means and having a. rest contact connected with a current source and a second contact connected through a resistance to ground, a gas discharge tube having a signal grid connected to the relay and adapted to be connected to either the current source or the grounding resistance, time delay means including said resistance for retarding the firing ci said gas discharge tube when the switching relay connects the signal grid with the ground, and a motor control relay energized from the plate of said gas discharge tube.

3. In a motor control apparatus for alternately operating each of two motor driven devices in cycles under control of a selected frequency trace actuated by the currently operating motor driven device, initiating means for effecting the start of either motor driven device before the conclusion o f operation by a currently operating motor driven device, comprising in combination, a control motor and cycling switches driven thereby, a control relay for cycling said control motor, an electron tube with circuit means for energizing the control relay, time consuming means for ring said electron tube and including a resistor-capacitor network, an electric energy source for said relay and said electron tube, switching relay means for impressf ing a low potential current upon the signal grid o1" said electron tube and to charge the capacitor of said resistor-capacitor network, said switching relay means also being adapted to ground the signal grid of said electron tube through the resistor of said resistor-capacitor network for retarding the ring o f said electron tube, high potential means for energizing said switching relay means, and an electronic initiating network for discriminating the selected frequency and for developing from said selected frequency an amplied actuating impulse free from associated frequencies for control of said switching relay.

4. In a control system for successively operating a plurality of photographic projectors, the combination with a plurality of sets of cam operated switches for control of motors, lamps, sound heads and shutters cf associated projectors, and a cycling motor for actuating said sets of switches, of an initiating means for control of said cycling motor comprising an electron relay circuit having a gas discharge tube rendered conductive by connecting its signal grid to ground potential, a control relay having its winding in the plate circuit of said gas discharge tube, a switching relay normally maintaining the bias cf said signal grid at a potential remote from conductivity, energizing means for said switching relay and operative to connect said signal grid to ground, time consuming means made operative when the switching relay is energized for delaying the return of grid bias to tube conductivity, and electronic means rendered operative by the operation o f one projector for translating 10 a, selected frequency signal into an actuating impulse isolated from associated frequencies oi music and its overtones for starting the grounded discharge of the time consuming means lfor ring the gas discharge tube.

5. In a control system of the class described, a control source including a variable frequency generating device superimposed with a selected frequency of definite duration, electronic means for separating and isolating the selected frequency and translating it into a control signal of substantial electrical energy enduring for the said definite duration, means for reception of said control signal including a switching relay,

a gas discharge tube circuit controlled by said switching relay, means including said switching relay for overbiasing the grid of said discharge tube, means including said switching relay for reducing the bias of said discharge tube to effect iring of the tube incident to duration of the control signal, a switching motor whose energization is controlled by the gas discharge tube, and means actuated by the ring of said gas discharge tube for temporarily completing the reduced bias of said tube in shunt with the reduced bias established by said switching relay.

GEO. H. LISTER.

ALBERT R. PANETTA.

No references cited. 

